This invention relates to equipment for sanitary clamps for joining two flanged tubes or pipes together in a way that seals the junction of the two flanged ends and which allows the tubes and associated equipment to be cleaned in place by an injection of a cleaning fluid. The invention is more particularly concerned with a sanitary clamp that employs a threaded closure, e.g., a bolt or an eyebolt and an associated wing nut or hex nut to secure the clamp onto the flanged tube ends, and which when screwed down onto the clamp has no exposed screw threads, which can harbor bacteria or other contaminants and which are difficult to clean.
There are a number of styles of sanitary clamps which go by names such as tri-clamp, C-clamp, tri-clover, ferrule, sanitary ferrule, hygienic clamp, hygienic clamp ferrule, and hygienic clamp union.
Over the past decade sanitary piping and sanitary vessels have received a great deal of scrutiny of their product design and the quality of finishes to optimize cleanability. Clamps of the type described have facilitated the cleaning of the interior of the sanitary flow line and any associated vessel or component. However, in more recent years this scrutiny has been extended to the outside of piping and the outside of vessels, that is, to the entire clean area, including the exterior of the sanitary lines. Some sanitary lines including piping and vessels are now installed in clean manufacturing environments, i.e., clean rooms, where airborne particulate contamination has to be monitored and controlled. The response to this has been to improve the finishes and design of external components so they can be cleaned. Despite the increased interest in hygienic designs and avoiding structures and surfaces that may collect and harbor contaminates, there have been no major changes to the designs of sanitary clamps, which continue to be offered only with exposed threads.
Equipment located in clean areas of food, dairy, or pharmaceutical processing or other comestible liquid processing environments are required to be cleaned periodically by wash-down, or manually cleaned by wipe-down with harsh cleaning solutions, i.e., caustics. All components of the food or other sanitary processing line have to be capable of being chemically cleaned or steam cleaned, and then rinsed in a pressure wash.
Despite these requirements, designs for the sanitary clamp itself still employ closures with exposed threads which are notorious for collecting and harboring bacteria. Often a valve cluster or other processing equipment may have many sanitary clamps, which currently all have one or two bolt closures where there are exposed threads. This possible source of contamination in the clean environment has been overlooked and there has been no effort made to address it. These sanitary clamps employ either an eyebolt (swing bolt) and a wing nut or two common bolts and wing nuts or hex nuts, depending on the design. In either case these are fully threaded, and the wing nuts and hex nuts are of designs that leave their internal female threads exposed to the ambient, as well of the male threads of the threaded bolt shafts.
With this construction it is not possible for all external exposed surfaces to be completely cleaned by washing it and rinsing it with a cleaning fluid, because of the difficulty in cleaning the threads. Any screw threads would have to be sealed off and isolated from any contact with the ambient atmosphere, but this issue has been completely overlooked in the sanitary clamp art.